1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // <array>
10 
11 // const_reference operator[](size_type) const; // constexpr in C++14
12 // Libc++ marks it as noexcept
13 
14 #include <array>
15 #include <cassert>
16 
17 #include "test_macros.h"
18 
19 // std::array is explicitly allowed to be initialized with A a = { init-list };.
20 // Disable the missing braces warning for this reason.
21 #include "disable_missing_braces_warning.h"
22 
23 
24 TEST_CONSTEXPR_CXX14 bool tests()
25 {
26     {
27         typedef double T;
28         typedef std::array<T, 3> C;
29         C const c = {1, 2, 3.5};
30         LIBCPP_ASSERT_NOEXCEPT(c[0]);
31         ASSERT_SAME_TYPE(C::const_reference, decltype(c[0]));
32         C::const_reference r1 = c[0];
33         assert(r1 == 1);
34         C::const_reference r2 = c[2];
35         assert(r2 == 3.5);
36     }
37     // Test operator[] "works" on zero sized arrays
38     {
39         {
40             typedef double T;
41             typedef std::array<T, 0> C;
42             C const c = {};
43             LIBCPP_ASSERT_NOEXCEPT(c[0]);
44             ASSERT_SAME_TYPE(C::const_reference, decltype(c[0]));
45             if (c.size() > (0)) { // always false
46                 C::const_reference r = c[0];
47                 (void)r;
48             }
49         }
50         {
51             typedef double T;
52             typedef std::array<T const, 0> C;
53             C const c = {};
54             LIBCPP_ASSERT_NOEXCEPT(c[0]);
55             ASSERT_SAME_TYPE(C::const_reference, decltype(c[0]));
56             if (c.size() > (0)) { // always false
57               C::const_reference r = c[0];
58               (void)r;
59             }
60         }
61     }
62 
63     return true;
64 }
65 
66 int main(int, char**)
67 {
68     tests();
69 #if TEST_STD_VER >= 14
70     static_assert(tests(), "");
71 #endif
72   return 0;
73 }
74